In recent years, a QoS (Quality of Service) control can be carried out in an application unit or a user unit in a computer network.
This is realized by identifying an application and a user under the condition of flow data of an application communication (a set of a source IP address, a destination IP address, a protocol, a source port number, a destination port number) and executing processing of a packet primarily in a router and a switch which exist on the communication path.
In such a conventional computer network, because the flow data which contains the IP address for identifying a user is statically set to the router and the switch, there is a problems that the QoS control cannot be carried out in the communication in a user unit when the IP address of the user is changed dynamically in case of a mobile terminal.
As for this problem, Patent Literature 1 (Japanese Patent No. 3,750,634) discloses the QoS control method in a user unit, in which an IP address and a user are related to each other through the user authentication, and the QoS policy is set dynamically according to the allocated QoS data, (reference to paragraphs [0039] to [0060] and FIG. 3 of Patent Literature 1).
However, in Patent Literature 1, there was a problem that the switches on the communication route must have a function of authentication QoS. When there is a network which is composed of usual switches on the communication route, the QoS control to the user cannot be carried out in the network.